The use of catalytic alkylation processes to produce branched hydrocarbons having properties that are suitable for use as gasoline blending components is well known in the art. Generally, the alkylation of olefins by saturated hydrocarbons, such as isoparaffins, is accomplished by contacting the reactants with an acid catalyst to form a reaction mixture, settling the mixture to separate the catalyst from the hydrocarbons and further separating the alkylation reactor effluent, for example, by fractionation, to recover the separate product streams. Normally, the alkylation reactor effluent of the alkylation process contains hydrocarbons having five to ten carbon atoms per molecule, preferably seven to nine carbons atoms per molecule. In order to have the highest quality gasoline blending stock, it is preferred for the alkylate hydrocarbons formed in the alkylation process to be highly branched and contain seven to nine carbon atoms per molecule.
Recent efforts to improve conventional hydrogen fluoride catalyzed alkylation processes have resulted in the development of new catalyst compositions that contain hydrogen fluoride and a volatility reducing additive. These new catalyst compositions have been found to be quite effective as an alkylation catalyst and to provide many other favorable benefits. However, it has also been found that in the alkylation process that uses the catalyst mixture containing hydrogen fluoride and such additive there is an increase in the production of undesirable organic fluorides. In fact, as the concentration of hydrogen fluoride in the new catalyst composition becomes more dilute, the amount of organic fluorides produced in the alkylation process increases. Organic fluorides produced can include, but are not limited to, organic fluorides having in the range of from about 3 to about 14 carbon atoms per molecule. Typical organic fluorides produced can include, but are not limited to, 2-fluoropropane, 2-fluorobutane, 2-fluoro-2-methylpropane, 2-fluoropentane, 2-fluoro-2-methylbutane, 2-fluoro-3-methylbutane, methylfluorobutane isomers, 2-fluorohexane, 3-fluorohexane, methylfluoropentanes, dimethylfluorobutanes, fluoroheptanes, fluoromethylhexanes, dimethylfluoropentanes, fluorooctanes, fluoromethylheptanes, dimethylfluorohexanes, fluorotrimethylpentanes fluorononanes, fluoromethyloctanes, dimethylfluoroheptanes, fluorotrimethylhexanes.
In many instances, it is not desirable for the product streams to have an excessively high concentration of organic fluorides.
Therefore, development of an efficient process for reducing the level of organic fluorides present in a hydrocarbon mixture would be a significant contribution to the art.